In a wafer level lens process in which a plurality of lenses is disposed on a wafer substrate in the planar direction, it is difficult to obtain the shape accuracy and/or the position accuracy when the lenses are formed. Particularly, a high level of accuracy may be needed in a process of laminating the wafer substrates so as to manufacture a layered lens structure. Thus, it may difficult to mass produce three or more layers that are laminated with such a high level of accuracy.
Various technologies have been proposed for wafer level lens production. For example, PTL 1 discloses a method of laminating a wafer substrate by directly using a lens material as an adhesive when the lens material is charged (loaded) into a through-hole formed in a substrate so as to form a lens.